If he is a full time college student under the age of 24 in the tax year then you should be able to claim him as your dependent under the Qualifying Child rules. You do NOT report his earned income on your tax return.
To be a Qualifying Child -
1. The child must be your son, daughter, stepchild, foster child, brother, sister, half brother, half sister, stepbrother, stepsister, or a descendant of any of them.
2. The child must be (a) under age 19 at the end of the year, (b) under age 24 at the end of the year and a full-time student or (c) any age and permanently and totally disabled.
3. The child must have lived with you for more than half of the year. Temporary absences while away at college are considered living with you.
4. The child must not have provided more than half of his or her own support for the year.
5. If the child meets the rules to be a qualifying child of more than one person, you must be the person entitled to claim the child as a qualifying child.
6. The child must be a U.S. citizen or U.S., Canada or Mexico resident for some portion of the year.
7. The child must be younger than you unless disabled.
If his earned income is from wages that are reported on a W-2 he does not have to file a tax return since his income is below the requirement for filing. If he had taxes withheld from his wages he should file a return to get a refund of the taxes. If he does file and you are claiming him as a dependent make sure that he indicates on his tax return that he can be claimed as a dependent.
If his earned income is from self-employment he Must file a tax return since his income is $400 or more. He reports the his self-employment income and expenses on Schedule C which is included with and is part of his federal tax return Form 1040. Again he still must indicate he is a dependent if you are claiming him as a dependent on your tax return.
